Added indef. article a before language-independent

Corrected table and list layout in Json paragraph

Update table XML section,corrected link to XmlListmodel

Added Oxford comma in several passages in the text

Change-Id: I878af462d1c136a5c37a1c961f80560c77674acd
Reviewed-by: Martin Smith <martin.smith@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>